Unauthorized Device Detection Device, Unauthorized Device Detection System, Unauthorized Device Detection Method, Program, Recording Medium, and Device Information Update Method

ABSTRACT

An unauthorized apparatus detection device, playback device, unauthorized apparatus detection system, information collection device, unauthorized apparatus detection method, a program, recording medium, apparatus information update method, and integrated circuit can detect clones of a playback device. In a management server  2 , a reception processing unit  241  acquires a user terminal identifier and a first random number from a user terminal targeted for unauthorized apparatus detection, judges whether a second management server random number, which is stored in a storage unit  23  in correspondence with the user terminal identifier, matches the first user terminal random number. If the two fail to match, a display unit  22  displays a message indicating that a clone exists. If the two match, a terminal information generation unit  243  generates a new random number, and writes the generated random number as the second random number in the storage unit  23 . A transmission processing unit  246  transmits the generated random number to the user terminal via a transmission/reception unit  246  and the user terminal updates the first user terminal random number to the generated random number.

TECHNICAL FIELD

The present invention relates to an unauthorized apparatus detectiondevice for detecting unauthorized devices produced by copying, and inparticular, to technology for detecting clone playback devices used toplay copyrighted content such as movies and music.

BACKGROUND ART

In recent years the existence of clone devices produced by copyingauthorized playback devices has become a major problem. To protectcopyright, only authorized devices are permitted to decrypt and playbackencrypted content. However, each clone device has a device key identicalto that held by an authorized playback device, and decrypts and playsencrypted content using a method identical to that used by theauthorized playback device. Anyone in possession of the clone device cantherefore fraudulently watch and listen to the content.

With regard to this problem, Patent Document 1 discloses a method fordetecting clone terminals in the case where the authorized mobileterminal is a mobile phone.

According to Patent Document 1, a clone terminal detection device judgesthat a clone terminal exists if two or more mobile terminals aredetected to be simultaneously under the control of a plurality of basestations.

Patent Document 1: Japanese Patent Application publication No.2000-184447

DISCLOSURE OF THE INVENTION Problems the Invention Aims to Solve

The above technology, however, is dependent upon each mobile terminalregistering a current position with a base station, and is thereforeinappropriate for a system including content playback devices that donot perform position registration.

In view of this problem, the present invention aims to provide anunauthorized apparatus detection device, a content playback device, anunauthorized apparatus detection system, a program, an informationcollecting device, an unauthorized apparatus detection method, aprogram, a recording medium, an apparatus information update method, andan integrated circuit, which are able to detect clones of contentplayback devices.

Means to Solve the Problem

In order to achieve the above object, the unauthorized apparatusdetection device of the present invention is an unauthorized apparatusdetection device for detecting an unauthorized apparatus produced bycopying, including: a distribution unit operable to store a firstverification value in correspondence with a verification apparatusidentifier, generate a second verification value that differs from thefirst verification value, store the second verification value in placeof the first verification value, and distribute the second verificationvalue to an apparatus that is storing the verification apparatusidentifier; an acquiring unit operable to acquire from a portable mediuma target apparatus identifier and a verification value that have beenwritten to the portable medium by a detection target apparatus; ajudging unit operable, if the target apparatus identifier matches theverification apparatus identifier, to judge whether or not the acquiredverification value matches the second verification value; and aregistering unit operable, if the judging unit judges negatively, toregister the target apparatus identifier on an unauthorized apparatuslist.

The unauthorized apparatus detection device of the present inventionjudges whether the detection target apparatus storing a target apparatusidentifier identical to the verification apparatus identifier stores anupdated verification value. Consequently, it is possible to detect anirregular state in which i) an apparatus storing the verificationapparatus identifier and pre-update verification value coexists with ii)another apparatus storing the verification apparatus identifier and thepost-update verification value.

The registering unit registers the target apparatus identifier on anunauthorized apparatus list if the judging unit judges negatively. Thisregistration of unauthorized apparatuses used herein refers to a conceptfor performing some kind of processing on non-matching apparatusidentifiers.

For example, the unauthorized apparatus detection device may store aplurality of target apparatus identifiers in RAM, distinguish the targetapparatus identifier corresponding to a non-matching random number fromthe other target apparatus identifiers, and transmit the result to aseparately provided display unit. This operation is considered toregister the target apparatus identifiers corresponding to non-matchingrandom numbers on an unauthorized apparatus list, and transmit theunauthorized apparatus list to the display unit. Note that it issufficient to store the unauthorized apparatus list in volatile memory,rather than in non-volatile memory.

If the judging unit judges affirmatively, the distribution unit may befurther operable to generate a third verification value that differsfrom the second verification value, store the third verification valuein place of the second verification value, and distribute the thirdverification value to the detection target apparatus.

With this construction, the verification value of the detection targetapparatus, which corresponds to the verification apparatus identifier,is updated. Consequently, the detection target apparatus and theunauthorized device detection apparatus can bother store a newverification value.

By repeating similar processing (i.e. by having the acquisition unitacquire the target apparatus identifier and the verification value andhaving the judgment unit judge whether the verification values match),the unauthorized apparatus detection device is able to detectunauthorized target apparatuses that are storing the verification targetidentifier, since the verification values of these devices will not beupdated.

The present invention may be the unauthorized apparatus detection devicefurther including: a title key storage unit operable to store a titlekey for decrypting encrypted content, wherein if the judging unit judgesaffirmatively, the distribution unit further distributes the title keyto the detection target apparatus.

With this construction, only detection target apparatus judged to beauthorized apparatus is permitted to decrypt and play back the content,and unauthorized playback can therefore be prevented.

The present invention may be the detection target apparatus storingtherein a private key and the unauthorized apparatus detection devicefurther including: a title key storage unit operable to store a titlekey for decrypting encoded content; a duplicate key storage unitoperable to store, in correspondence with the verification apparatusidentifier, a duplicate key that is a copy of the private key; and anencrypted title key generation unit operable to encrypt the title keyusing the duplicate key to generate an encrypted title key, wherein ifthe judging unit judges affirmatively, the distribution unit furtherdistributes the encrypted title key to the detection target apparatus.

With this construction, only detection target apparatus judged to beauthorized apparatus can decrypt the title key, and unauthorizedplayback can therefore be prevented.

The present invention may be the unauthorized apparatus detection deviceof, further including: a counting unit operable to count a number ofaffirmative judgments by the judging unit; and a count judging unitoperable to judge whether the total number of affirmative judgmentsexceeds a predetermined number, wherein if the total number exceeds thepredetermined number, the distribution unit is further operable togenerate a third verification value that differs from the secondverification value, replace the first verification value with the thirdverification value, and distribute the second verification value to thedetection target apparatus.

The present invention may be the unauthorized apparatus detectiondevice, further including: a period measuring unit operable to measure aperiod since a last verification value distribution by the distributionunit; and a period judging unit operable to judge whether the totalperiod exceeds a predetermined period, wherein if the total periodexceeds the predetermined period, the distribution unit is furtheroperable to generate a third verification value that differs from thesecond verification value, replace the second verification value withthe third verification value, and distribute the third verificationvalue to the detection target apparatus.

These constructions reduce the number of times a new verification valueis generated and updated, thereby reducing the amount of work needed forthe update processing.

The distribution unit may be operable to generate a random number to useas each verification value.

This construction is able to reduce the risk of unauthorized playbackresulting from the verification being guessed.

The content playback device of the present invention includes: a storageunit operable to store, in correspondence with an apparatus identifier,a first verification value generated by an unauthorized apparatusdetection device for detecting an unauthorized apparatus produced bycopying; a notification unit operable to notify the unauthorizedapparatus detection device of the apparatus identifier and firstverification value; an acquiring unit operable to acquire from aportable medium an apparatus identifier and a second verification valuethat have been written, in response to the notification, on the portablemedium by the unauthorized apparatus detection device, the secondverification value having been generated by the unauthorized apparatusdetection device; and an update unit operable, if the acquired apparatusidentifier matches the apparatus identifier stored in the storage unit,to replace the first verification value with the second verificationvalue.

With this construction, the content playback device overwrites thestored verification value with the verification value generated by theunauthorized apparatus detection device. Consequently, the contentplayback device is able to inform the unauthorized detection device ofthe latest verification value generated by the unauthorized apparatusdetection device. The authorized playback device is thus prevented fromtransmitting an old verification value and being mistakenly judged to bean unauthorized device.

An unauthorized apparatus detection system of the present invention isan unauthorized apparatus detection system that detects an unauthorizedapparatus produced by copying, and includes an unauthorized apparatusdetection device and a plurality of detection target apparatuses, eachdetection target apparatus including: a storage unit operable to store afirst verification value in correspondence with a target apparatusidentifier; a notification unit operable to notify the unauthorizedapparatus detection device of the target apparatus identifier and thefirst verification value; an update information acquiring unit operableto acquire, from the unauthorized apparatus detection device, averification apparatus identifier and a second verification value thatis generated by the unauthorized apparatus detection device; and anupdate unit operable, if the verification apparatus identifier matchesthe target apparatus identifier, to replace the first verification valuewith the second verification value, and the unauthorized apparatusdetection device including: a distribution unit operable to generate asecond verification value that differs from a first verification valuestored in correspondence with a verification apparatus identifier, storethe second verification value in correspondence with the verificationapparatus identifier in place of the first verification value, anddistribute the verification apparatus identifier and the secondverification value to an apparatus that is storing the verificationapparatus identifier; an acquiring unit operable to acquire a targetapparatus identifier and a verification value from any one of thedetection target apparatuses; a judging unit operable, if the receivedtarget apparatus identifier matches the verification apparatusidentifier, to judge whether or not the acquired verification valuematches the second verification value, and a registering unit operable,if the judging unit judges negatively, to register the target apparatusidentifier on an unauthorized apparatus list.

With this construction, the verification value is updated in apparatusthat is judged to be authorized. Further, the unauthorized devicedetection apparatus judges whether the detection target device, which isstoring a target apparatus identifier identical to the verificationapparatus identifier, is storing the updated verification value. Theunauthorized device detection apparatus can thus detect the irregularstate in which i) an apparatus that has been judged to be authorizedcoexists with ii) an apparatus storing the verification identifier andthe pre-update verification value.

The notification unit may be further operable to write the targetapparatus identifier and the first verification value to a portablemedium, and the acquiring unit may be further operable to read thetarget apparatus identifier and the verification value from the portablemedium via an information collecting device.

The information collecting device may include: a reading unit operableto read from the portable medium the target apparatus identifier and theverification value that are written in the portable medium; and atransmission unit operable to transmit the target apparatus identifierand the verification value, and the acquiring unit may acquire thetarget apparatus identifier and the verification value from theinformation collecting device.

With this construction, the information collection device acquires theverification value from detection target device via the portable medium,and transmits the verification value to the unauthorized apparatusdetection device via a communications channel. Thus, even if thedetection target apparatuses are geographically dispersed, theverification values stored by each detection target device can becollected together in the unauthorized apparatus detection device.

An information collecting device of the present invention is aninformation collecting device for transmitting, to an unauthorizedapparatus detection device for detecting unauthorized apparatus producedby copying, information stored by a detection target apparatus that is atarget of the detection, the detection target apparatus storing a targetapparatus identifier and a verification value generated by theunauthorized apparatus detection device, and the unauthorized apparatusdetection device generating the verification value, storing thegenerated verification value in correspondence with a verificationapparatus identifier, acquiring a target apparatus identifier and averification value, if the target apparatus identifier matches theverification apparatus identifier, judging whether the storedverification value matches the acquired verification value, and ifjudging negatively, registering the target apparatus identifier on anunauthorized apparatus list, the information collecting deviceincluding: a reading unit operable to read from the portable medium thetarget apparatus identifier and the verification value that have beenwritten to the portable medium by the detection target apparatus; and atransmission unit operable to transmit the read target apparatusidentifier and the read verification value to the unauthorized apparatusdetection device.

With this construction, the verification value acquired from thedetection target apparatus via the portable medium is transmitted to theunauthorized apparatus detection device via a communications channel.Thus, even if the detection target apparatuses are geographicallydispersed, the verification values stored by each detection targetdevice can be collected together in the unauthorized apparatus detectiondevice.

An unauthorized apparatus detection method of the present invention isan unauthorized apparatus detection method for detecting an unauthorizedapparatus produced by copying, including: distribution step of storing afirst verification value in correspondence with a verification apparatusidentifier, generating a second verification value that differs from thefirst verification value, storing the second verification value in placeof the first verification value, and distributing the secondverification value to an apparatus that is storing the verificationapparatus identifier; an acquiring step of acquiring from a portablemedium a target apparatus identifier and a verification value that havebeen written to the portable medium by a detection target apparatus; ajudging step of, if the target apparatus identifier matches theverification apparatus identifier, judging whether or not the acquiredverification value matches the second verification value; and aregistering step of, if the judging unit judges negatively, registeringthe target apparatus identifier on an unauthorized apparatus list.

A computer program of the present invention is a computer program usedin a storage unit-equipped unauthorized apparatus detection unit fordetecting an unauthorized apparatus produced by copying, including: adistribution step of storing a first verification value incorrespondence with a verification apparatus identifier, generating asecond verification value that differs from the first verificationvalue, storing the second verification value in place of the firstverification value, and distributing the second verification value to anapparatus that is storing the verification apparatus identifier; anacquiring step of acquiring from a portable medium a target apparatusidentifier and a verification value that have been written to theportable medium by a detection target apparatus; a judging step of, ifthe target apparatus identifier matches the verification apparatusidentifier, judging whether or not the acquired verification valuematches the second verification value; and a registering step of, if thejudging unit judges negatively, registering the target apparatusidentifier on an unauthorized apparatus list.

A recording medium of the present invention is computer readable, andhas the computer program recorded thereon.

With this construction, the verification value stored by the apparatusis updated in apparatus that is judged to be authorized. Theunauthorized apparatus detection device judges whether or not thedetection target apparatus storing a target apparatus identifieridentical to the verification apparatus identifier is storing theupdated verification value. Consequently, the unauthorized apparatusdetection device is able to detect the irregular state in which theapparatus judged to be authorized coexists with an apparatus storing theverification apparatus identifier and the pre-update verification value.

An apparatus information update method of the present invention is anapparatus information update method used by a content playback devicefor performing playback of content, the content playback deviceincluding a storage unit operable to store, in correspondence with anapparatus identifier, a first verification value generated by anunauthorized apparatus detection device for detecting an unauthorizedapparatus produced by copying; and the apparatus information updatemethod including: a notification step of notifying the unauthorizedapparatus detection device of the apparatus identifier and firstverification value; an acquiring step of acquiring from a portablemedium an apparatus identifier and a second verification value that havebeen written, in response to the notification, on the portable medium bythe unauthorized apparatus detection device, the second verificationvalue having been generated by the unauthorized apparatus detectiondevice; and an update step of, if the acquired apparatus identifiermatches the apparatus identifier stored in the storage unit, replacingthe first verification value with the second verification value.

A computer program of the present invention is a computer program usedby a content playback device for performing playback of content, thecontent playback device including a storage unit operable to store, incorrespondence with an apparatus identifier, a first verification valuegenerated by an unauthorized apparatus detection device for detecting anunauthorized apparatus produced by copying; and the computer programincluding: a notification step of notifying the unauthorized apparatusdetection device of the apparatus identifier and first verificationvalue; an acquiring step of acquiring from a portable medium anapparatus identifier and a second verification value that have beenwritten, in response to the notification, on the portable medium by theunauthorized apparatus detection device, the second verification valuehaving been generated by the unauthorized apparatus detection device;and an update step of, if the acquired apparatus identifier matches theapparatus identifier stored in the storage unit, replacing the firstverification value with the second verification value.

A recording medium of the present invention is a computer-readablerecording medium having recorded thereon the computer program

An integrated circuit of the present invention is an integrated circuitused content playback device for performing playback of content,including: a storage unit operable to store, in correspondence with anapparatus identifier, a first verification value generated by anunauthorized apparatus detection device for detecting an unauthorizedapparatus produced by copying; a notification unit operable to notifythe unauthorized apparatus detection device of the apparatus identifierand first verification value; an acquiring unit operable to acquire froma portable medium an apparatus identifier and a second verificationvalue that have been written, in response to the notification, on theportable medium by the unauthorized apparatus detection device, thesecond verification value having been generated by the unauthorizedapparatus detection device; and an update unit operable, if the acquiredapparatus identifier matches the apparatus identifier stored in thestorage unit, to replace the first verification value with the secondverification value.

With this construction, the content playback device overwrites thestored verification value with the verification value generated by theunauthorized apparatus detection device. Consequently, the contentplayback device is able to communicate, to the unauthorized detectiondevice, the latest verification value generated by the unauthorizedapparatus detection device. The authorized playback device is thusprevented from transmitting an old verification value and beingmistakenly judged to be an unauthorized device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the construction of a clone terminal finding system of anembodiment of the present invention;

FIG. 2 shows a data structure of a first portable medium of theembodiment of the present invention;

FIGS. 3A to 3D show data structures of a second portable medium of theembodiment of the present invention;

FIG. 4 is a block diagram showing a construction of a management serverof the embodiment of the present invention;

FIG. 5 shows a data structure stored in a storage unit of the managementserver of the embodiment of the present invention;

FIG. 6 is a flowchart showing an example of operations of the managementserver of the present invention;

FIG. 7 is a block diagram showing a construction of an informationcollection server of the embodiment of the present invention;

FIG. 8 is a flowchart showing operations of an information collectionserver of the embodiment of the present invention;

FIG. 9 is a block diagram showing a construction of a user terminal ofthe embodiment of the present invention;

FIG. 10 shows a data structure stored in the storage unit of theembodiment of the present invention;

FIG. 11 is a flowchart showing initial setting operations and updateoperations of the embodiment of the present invention, when the secondportable medium from the user terminal is inserted; and

FIG. 12 is a flowchart showing content playback processing in the userterminal of the embodiment of the present invention.

REFERENCE NUMERALS

-   1 Clone terminal finding system-   2 Management server-   3 Information collection server-   4 First portable medium-   5 a to 5 m Second portable media-   6 a to 6 n User terminals-   21 Transmission/reception unit-   22 Display unit-   23 Storage unit-   24 Control unit-   31 Transmission/reception unit-   32 Second portable medium access unit-   33 External input unit-   34 Control unit-   61 Second portable medium access unit-   62 First portable medium access unit-   63 Output unit-   64 Storage unit-   65 Control unit-   241 Reception processing unit-   242 Terminal information verifying unit-   243 Terminal information generation unit-   244 Title key encryption unit-   245 Transmission data generation unit-   246 Transmission processing unit-   341 Second portable medium insertion processing unit-   342 Title information acquisition unit-   343 Transmission data generation unit-   344 Transmission processing unit-   345 Reception processing unit-   346 Second portable medium data writing unit-   651 Second portable medium insertion processing unit-   652 Terminal information writing unit-   653 Encryption title key decryption unit-   654 Terminal information update unit-   655 First portable medium insertion processing unit-   656 Descramble processing unit-   7 Communication channel

BEST MODE FOR CARRYING OUT THE INVENTION

The clone terminal finding system of a first embodiment of the presentinvention is a system for finding clone terminals which have beenmanufactured and sold by an unauthorized manufacturer or the like. Theseclone terminals are made by illegitimately copying a legitimatelymanufactured user terminal, such as a DVD player.

The following describes the clone terminal finding system with referenceto the drawings.

Concept

The clone terminal finding system 1 of the first embodiment of thepresent invention is constructed from a management server 2, aninformation collection server 3, a first portable medium 4, secondportable media 5 a to 5 m (where m is a natural number), user terminals6 a to 6 n (where n is a natural number), and a communications channel7.

The firstportablemedium4 is an optical disk (such as a DVD-ROM) havingrecorded thereon moving picture content that has been encrypted using atitle key. The first portable medium is sold in retail outlets.

The second portable media 5 a to 5 m are rewritable portable media (suchas SD cards) each capable of storing a key and terminal information. Thekey is required to decode the encrypted moving picture content recordedon the first portable medium 4, while the terminal information relatesto the user terminal and is required to find clone terminals. The secondportable media 5 a to 5 m are used to transfer data back and forthbetween the information collection server 3 and the user terminals 6 ato 6 n.

The user terminals 6 a to 6 n are playback devices (such as DVD players)for decrypting and playing back the moving picture content recorded onthe first portable media 4. Each of the terminals 6 a to 6 n stores apre-allocated private key, generates the title key for the encryptedmoving picture content using the private key and information stored on acorresponding one of the second portable media 5 a to 5 n, decrypts theencrypted content, and plays back the result.

The information collection server 3 is a computer device installed inthe retail outlet that sells the first portable medium 4, and is capableof reading data from and writing data to the second portable media 5 ato 5 m. When one of the second portable media 5 a to 5 m is inserted,the information collection server 3 reads the recorded terminalinformation, transmits the read terminal information to the managementserver 2 which is connected via a communication channel 7 in a network,acquires in response information from the management server 2, andwrites the acquired information to the inserted second portable medium.

The management server 2 is a computer terminal for finding cloneterminals. On receipt of terminal information pertaining to one of theuser terminals 6 a to 6 n from the information collection server 3 viathe communication channel 7, the management server 2 judges whether theuser terminal indicated by the acquired terminal information is a cloneterminal. If judging in the negative, the management server 2 generatesan encrypted title key, which is an encrypted version of the title keyfor the moving picture content, updates information for updating theterminal information stored by the user terminal, and transmits theencrypted title key and the update information to the informationcollection server 3. The clone terminal is assumed to be a copy and tohave stored therein a private key identical to the one stored by thelegitimate user terminal used to make the copy. Processing relating tothe judgment as to whether a given terminal is a clone terminal isdescribed below.

The processing for discovering a clone terminal is described below withreference to an example in which the user who wishes to buy and playback the content is in possession of the user terminal 6 a and thesecond portable medium 5 a.

Firstly, the user inserts the second portable medium 5 a into the userterminal 6 a. The user terminal 6 a writes terminal information,including a user terminal identifier and the like, to the secondportable medium 5 a.

Next, the user takes the second portable medium 5 a to a retail outlet,and inserts the second portable medium 5 a into the informationcollection server 3, which is installed at the retail outlet.

The information collection server 3 reads the terminal information fromthe second portable medium 5 a, and transmits the terminal informationto the management server 2.

Based on the terminal information, the management server 2 judgeswhether the user terminal of the terminal information is a cloneterminal. If judging in the negative, the management server 2 generatesan encrypted title key by encrypting the title key using a private keyof the user terminal. The title key is the key used to encrypt themoving picture content recorded on the first portable medium 4. Notealso that the private key for the user terminal corresponds to theterminal information. The management server 2 further generates updateinformation for updating the terminal information stored by the userterminal, and transmits the encrypted title key and the updateinformation to the information collection server 3

The information collection server 3 writes the encrypted title key andthe update information to the second portable medium 5 a.

The user takes home the second portable medium 5 a and the purchasedfirst portable medium 4, and inserts the first portable medium 4 and thesecond portable medium 5 a into the user terminal 6 a.

The user terminal 6 a decrypts the encrypted title key to generate thetitle key, decrypts the encrypted moving picture content recorded on thefirst portable medium 4, plays back the result. The user terminal 6 aalso updates the stored terminal information based on the updateinformation.

Construction

Construction of First Portable Medium 4

The first portable medium 4 is a DVD-ROM having recorded thereon a titleidentifier and encrypted content corresponding to the content identifiedby the title identifier.

The title identifier uniquely specifies a title of a movie or songstored on the first portable medium 4, using a serial number (1, 2, 3, .. . ) or the like. The content is encoded in a format, such as the MPEG2 (Moving Picture Expert Group) format, which the user terminals areable to decode and play back or output to an external unit.

The first portable medium 4 may, for instance, store the titleidentifier 401 “TLID1” and the encrypted content 402 “ENCCNT1”, as shownin FIG. 2.

The ENCCNT1 is content “CNT1” encrypted using a title key “TLK1” thatcorresponds to a title identifier “TLID1”. ENCCNT1 can be expressed asEnc (TLK1, CNT1), where Enc (K, P) indicates a cipher text obtained byencrypting a plain text P using an encryption key K.

The encryption and decryption rely on a private key encryption method.In the present embodiment, the encryption may be block encryption AES.Since AES is a well-known method, a description of AES is omitted.

Construction of Second Portable Medium 5 a

The second portable medium 5 a is an SD card, and stores a user terminaltable.

The user terminal table is constructed from at one or more pieces ofuser terminal information. Each piece of user terminal informationincludes a user terminal identifier, a first user terminal randomnumber, a second user terminal random number, a title identifier, and anencrypted title key.

The user terminal identifier uniquely identifies one of the userterminals 6 a to 6 n.

The first user terminal random number is a random number that the userterminal corresponding to the user terminal identifier was storing whenthe second portable medium 5 a was last inserted. The user terminalwrites the first random number to the second portable medium 5 a at thistime.

The second user terminal random number is generated by the managementserver 2 in order to update the first random number stored by the userterminal. The second user terminal random number is written to thesecond portable medium by the information collection server 3, whichreceives the second user terminal random number from the managementserver 2.

The title identifier uniquely identifies the content recorded on thefirst portable medium 4, and is written to the second portable medium 5a by the information collection server 3.

The encrypted title key is obtained by encrypting the title key thatcorresponds to the title identifier, using a private key stored by theuser terminal identified by the user terminal identifier.

The first user terminal random number, the second user terminal randomnumber, the private key, and the title key may all be 128-bit naturalnumbers.

A value of “0” for the second user terminal random number indicates thatan update of the first terminal random number stored in the userterminal is not required. A value of “0” for the encrypted title keyindicates that the encrypted title key is either invalid or notrecorded.

The second portable medium 5 a may store a user terminal table 501, asshown in FIG. 3C. The user terminal table 501 includes pieces of userterminal information 531 each constructed from a user terminalidentifier 511 “TMIDa”, a first user terminal random number 512 “TMRND1a”, a second user terminal random number “TMRDN2 a”, a title key“TLID1”, and an encrypted title key “Enc(IKa, TLK1).

Construction of Management Server 2

The management server 2 is constructed from a transmission/receptionunit 21, a display unit 22, a storage unit 23, and a control unit 24, asshown in FIG. 4.

The management server 2 is realized using a computer system constructedfrom a microprocessor, ROM, RAM, a hard disk unit, a display unit, akeyboard, a mouse, a modem, and the like. A program is stored in the RAMand/or in the hard disk unit. The management server 2 realizes itsfunctions by the processor operating in accordance with the computerprogram.

The transmission/reception unit 21 is a modem or the like whichexchanges data with the information collection server 3 via thecommunication channel 7 using a communication protocol such as TCP/IP.

The display unit 22 is a display device such as a liquid crystaldisplay. On receipt of a display instruction from the control unit 24,the display unit 22 displays a screen based on the instruction.

The storage unit 23 stores a terminal management table 251, and a titlemanagement table 252, as shown in FIG. 5.

The terminal management table 251 is constructed from a plurality ofpieces of terminal information. Each piece includes a user terminalidentifier, a first management server random number, a second managementserver random number, and a private key.

The user terminal identifier identifies one of. the user terminals 6 ato 6 n.

The following describes TMIDx, which is the value of a user terminalidentifier that identifies a user terminal 6 x (where x is in the rangea to n).

The second management server random number is generated by the terminalinformation generation unit 243, which is described in a later section,and is used to update the user terminal random number held by the userterminal. The first management server random number is the random numbergenerated by the terminal information generation unit 243 directlybefore the second management server random number.

The first management server random number and the second managementserver random number may be 128-bit natural numbers. A value of “0”indicates that the second user terminal random number is invalid.

The private keys are unique device keys, each of which is assigned to adifferent one of the user terminals. A private key IKa is assigned tothe user terminal 6 a, a private key Ikb to the user terminal 6 b, andso on. Lastly, a private key Ikn is assigned to the user terminal 6 n.

The terminal management table 251may include a piece of terminalmanagement information 261, as shown in FIG. 5. The piece of terminalinformation 261 contains a user terminal identifier 262, which takes avalue “TMIDa” indicating the user terminal 6 a, a first managementserver random number 263 “CRND1 a”, a second management server randomnumber 264 “CRND2 a”, and the private key 265 “IKa”.

Every time an authorized user terminal is manufactured, apiece ofterminal information corresponding to a new user terminal is added tothe terminal information table 251.

The title management table 252 is made up of a plurality of pieces oftitle management information each including a title identifier and atitle key.

The title identifier identifies content, and the title key is forencrypting and decrypting the content identified by the title key.

The title management table 252 may include a piece of title managementinformation 271, as shown in FIG. 5. The piece of title managementinformation 271 contains a title identifier 272 “TLID1”, and a title key273, which is a title key for the content identified by TLID1.

For every new piece of content generated by content producers, acorresponding piece of title management information is added to thetitle management table 252.

As shown in FIG. 4, the control unit 24 is constructed from a receptionprocessing unit 241, a terminal information verifying unit 242, aterminal information generation unit 243, a title key encryption unit244, a transmission data generation unit 245, and a transmissionprocessing unit 246. The control unit 24 is, for example, aspecial-purpose microcomputer, which includes each of the abovefunctional units. Each unit may be realized by a program written in maskROM of the microcomputer. Alternatively, each unit may be an independentmicrocomputer.

The reception processing unit 241 receives the user terminal identifier,the first user terminal random number, and the title identifier from theinformation server 3 via the transmission/reception unit 21. Thereception processing unit then outputs the received user terminalidentifier and first user terminal random number to the terminalinformation verifying unit 242, and outputs the user terminal identifierand the title identifier to the title key encryption unit 244.

The terminal information verifying unit 242 receives the user terminalidentifier and the first user terminal random number from the receptionprocessing unit 241. The terminal information verifying unit 242 thenacquires the first management server random number that iscorrespondence with the received user terminal identifier from a storageunit 23. Moreover, if the second management server random numbercorresponding to the user terminal identifier is stored in the storageunit 23, the terminal information verifying unit 242 further acquiresthe second management server random number.

In the case where the second management server random number is storedin the storage unit 23, the terminal information verifying unit 242verifies whether or not the first user terminal random number matchesthe second management server random number.

If there is a match, the terminal information verifying unit 242 copiesthe value or the second management server random number over value ofthe first management server random number that is stored in the storageunit 23, and then deletes the second management server random number.The terminal information verifying unit 242 then outputs the userterminal identifier to the terminal information generation unit 243, andoutputs an encrypted key generation request to the title key encryptionunit 244.

When the second management server random number is stored but the firstuser terminal random number fails to match the second management serverrandom number, or when the second management server random number is notstored, the terminal information verifying unit verifies whether thefirst user terminal random number matches the first management serverrandom number.

If the first user terminal random number fails to match the firstmanagement server random number, the terminal information verifying unit242 causes the display unit 22 to display a screen indicating that theuser terminal corresponding to the user terminal identifier is a clone.If, on the other hand, the first user terminal random number matches thefirst management server random number, the terminal informationverifying unit 242 outputs the user terminal identifier to the terminalinformation generation unit 243, and outputs an encrypted title keygeneration request to the title key encryption unit 244.

The terminal information generation unit 243 receives the user terminalidentifier from the terminal information verifying unit 242, generates arandom number, and writes the generated random number over the secondmanagement server random number, which is stored in the storage unit 23in correspondence with the user terminal identifier. The terminalinformation generation unit 243 further outputs the same random numberto the transmission data generation unit 245 as a second user terminalrandom number. Here, the random number must be different from the onegenerated immediately before the random number. Also, since the methodfor generating the random number is a well-known, a description isomitted.

The title key encryption unit 244 receives the user terminal identifierfrom the reception processing unit 241, and receives the encrypted titlekey request from the terminal information verifying unit 242. The titlekey encryption unit 244 then acquires the private key corresponding tothe user terminal identifier from the terminal management table 252stored in the storage unit 23. Next the title key encryption unit 244encrypts the title key based on the acquired private key to generate anencrypted title key, and outputs the received title and the encryptedtitle key to the transmission data generation unit 245.

The transmission data generation unit 245 receives the second userterminal random number from the terminal information generation unit243, and receives the title identifier and the encrypted title key fromthe title key encryption unit 244. The transmission generation unit 245then generates update information data including the received seconduser terminal random number, the title identifier and the encryptedtitle key, and transmits the update information data to the transmissionprocessing unit 246.

The transmission processing unit 246 receives the update instructiondata from the transmission data generation unit 245, and transmits theupdate instruction data to the information collection server 3 via thetransmission/reception unit 21.

Construction of Information Collection Server

The information collection server 3 is constructed from atransmission/reception unit 31, a second portable medium access unit 32,an external input unit 33 and a control unit 34, as shown in FIG. 7.

The transmission/reception unit 31 is a modem or the like, andcommunicates data with the management server 2, via the communicationschannel 7, using TCP/IP communications protocol or the like.

The second portable medium access unit 32 is an SD card reader, andtransmits insertion notification to the control unit 34 when insertionof the second portable medium into an SD card slot (not depicted) isdetected. The SD card slot is provided in the information collectionserver 3. The second portable medium access unit 32 further acquiresdata from and writes data to the inserted second portable medium.

The external input unit 33 is an input device used by a user to inputthe title identifier. The input device permits input of the numbers 0 to9 and/or the letters A to Z, and may be a keyboard, a keypad, a mouse,or the like. The external input device transmits an inputted titleidentifier to the control unit 34.

In the present embodiment, the inputted title identifier is assumed tobe the TLID1.

The display unit 35 is a display device such as a liquid crystaldisplay. The display unit 35 receives a display instruction from thecontrol unit 34, and displays a screen based on the display instruction.

The control unit 34 includes a second portable medium insertionprocessing unit 341, a title information acquisition unit 342, atransmission data generation unit 343, a transmission processing unit344, a reception processing unit 345, and a second portable medium datawriting unit 346.

The control unit 34 is a special-purpose microcomputer or the likeincluding each of the functional units. Each of the functional units maybe written in the mask ROM of the microcomputer. Alternatively, each ofthe function units may be an independent microcomputer.

On receipt of the insertion notification from the second portable mediumaccess unit 32, the second portable medium insertion processing unit341, acquires the user terminal identifier and the first user terminalrandom number, which are recorded on the second portable medium, via thesecond portable medium access unit 32.

The second portable medium insertion processing unit 341 then outputsthe acquired user terminal identifier and first user terminal randomnumber to the transmission data generation unit 343, and outputs a titleinformation request to the title information acquisition unit 342.

On receipt of the title information request from the second portablemedium insertion processing unit 341, the title information acquisitionunit 342 transmits to the display 35 an instruction to display a messageprompting the user to input the title identifier, causing the display 35to display the message. Next, due to user input to the external inputunit 33, the title information acquisition unit receives the titleidentifier, and outputs the acquired title identifier to thetransmission data generation unit 343.

The transmission data generation unit 343, acquires the user terminalidentifier and the first user terminal random number from the secondportable medium insertion processing unit 341, and acquires the titleidentifier from the title information acquisition unit 342.

Next, the transmission data generation unit 343 generates transmissiondata for transmission to the management server 2. The transmission dataincludes the acquired user terminal identifier, the first user terminalrandom number and the user title identifier. The transmission datageneration unit 343 then outputs the transmission data to thetransmission processing unit 344.

The transmission processing unit 344, receives the transmission datafrom the transmission data generation unit 343, and transmits thetransmission data to the management server 2 via thetransmission/reception unit 31.

The reception processing unit 345 receives the update instruction data,which includes the second user terminal random number, the titleidentifier, and the encrypted title key, from the management server 2via the transmission/reception unit 31, and outputs the second userterminal random number, the title identifier, and the encrypted titlekey to the second portable medium data writing unit 346.

The second portable medium writing unit 346 receives the second userterminal random number, the title identifier and the encrypted titlekey, and records the received second user terminal random number, thetitle identifier and the encrypted title key on the second portablemedium via the second portable medium access unit 32.

Construction of User Terminal 6 a

The user terminal 6 a is constructed from a second portable mediumaccess unit 61, a first portable medium access unit 62, an output unit63, a storage unit 64, and a control unit 65.

The second portable medium access unit 61 is an SD card reader providedin the user terminal 6 a, and transmits insertion notification to thecontrol unit 65 when insertion of the second portable medium into an SDcard slot (not depicted) is detected. The second portable medium accessunit 32 further reads data from and writes data to the inserted secondportable medium.

The first portable medium access unit 62 is a DVD drive provided in theuser terminal 6 a, and transmits insertion notification to the controlunit 65 when insertion of the first portable medium into the DVD drive(not depicted) is detected. The first portable medium access unit 62further reads data from and writes data to the inserted first portablemedium.

The output unit 63 is a display adaptor, and is connected to an externaldisplay such as a liquid crystal or plasma display.

The storage unit 64 stores the user terminal identifier, the privatekey, a terminal stored random number, and a title information table.

The user terminal identifier identifies the user terminal, and iswritten to the user terminal before shipping.

The private key is different for every user terminal, and is written tothe user terminal before shipping.

The terminal stored random number is used by the management server 2 todetect clone terminals, and is given an initial value of 0 before theuser terminal is. shipped.

The title information table is constructed from at least one piece oftitle information, each piece including a title identifier and a titlekey. The title key is used to encrypt and decrypt the content identifiedby the title identifier.

When new title information is acquired, the acquired title informationis added to the title information table.

The storage unit 64 stores, for instance, a user terminal identifier 671“TMIDa”, a private key 672 “IKa”, a terminal stored random number 673“CRND1 a”, and a title information table 681, as shown in FIG. 10. Thetitle information table 681 includes a piece of title information 682made up of a title identifier 683 “TLID1” and a title key 684 “TLK1” forencrypting and decrypting the content identified by TLID1.

The control unit 65 is constructed from a second portable mediuminsertion processing unit 651, a terminal information writing unit 652,an encrypted title key decryption unit 653, a terminal informationupdate unit 654, a first portable medium insertion processing unit 655,and a descramble processing unit 656.

The control unit 65 is a special-purpose microcomputer, or the like,which includes each of the above functional units. Each unit may berealized by a program written in the mask ROM of the microcomputer.Alternatively, each unit may be an independent microcomputer.

On receipt of the insertion notification from the second portable mediumaccess unit 61, the second portable medium insertion processing unit 651acquires the user terminal identifier 671 “TMIDa”, which is stored inthe storage unit 64.

Next, the second portable medium insertion processing unit 651 verifies,via the second portable medium access unit 61, whether or not a userterminal identifier having a value of “TMIDa” is recorded on the secondportable medium. When the user identifier having a value of “TMIDa” isnot recorded on the second portable medium, the second portable mediuminsertion processing unit 651 outputs the user terminal identifier tothe terminal information writing unit 652, and ends the processing.

On the other hand, when the user terminal identifier having a value of“TMIDa” is recorded on the second portable medium, the second portablemedium insertion processing unit 651 verifies whether or not the seconduser terminal random number, the title identifier, and the encryptiontitle key are recorded in correspondence to the user terminal identifier“TMIDa”.

If the second user terminal random number is recorded in correspondencewith the user terminal identifier “TMIDa” on the second portable medium,the second portable medium insertion processing unit 651 outputs theread second user terminal random number to the terminal informationupdate unit 654, overwrites the value of the first user terminal randomnumber with the value of the second user terminal random number in thestorage unit 64, and deletes the second user terminal random number.

If the title identifier and encrypted title key are recorded on thesecond portable medium in correspondence to the user terminal identifier“TMIDa”, the second portable medium insertion processing unit 651 readsthe title identifier and the encrypted title key from the secondportable medium via the second portable medium access unit 61, outputsthe read title identifier and encrypted title key to the encrypted titlekey decryption unit 653, and deletes the title identifier and theencrypted title key from the second portable medium.

The encrypted title key decryption unit 653 receives the titleidentifier and the encrypted title key from the second portable mediuminsertion processing unit 651, and acquires the private key IKa from thestorage unit 64.

Next, the encrypted title key decryption unit 653 obtains the title keyby decrypting the encrypted title key using the private 36 key IKa, andadds the title identifier and the title key to the title informationtable 681.

The terminal information update unit 654 acquires the second userterminal random number from the second portable medium insertionprocessing unit 651, and updates the value of terminal stored randomnumber stored in the storage unit 64 with the value of the acquiredsecond user terminal random number.

The first portable medium insertion processing unit 655 receivesinsertion notification from the first portable medium access unit 62,and acquires the title identifier recorded on the first portable medium4 via the first portable medium access unit 62.

Next, the first portable medium insertion processing unit 655 judgeswhether or not the title key corresponding to the acquired titleidentifier is stored in the title information table 681 in the storageunit 64, and if judging in the affirmative, acquires the title key fromthe storage unit 64, and outputs the acquired title key to thedescramble processing unit 656.

The descramble processing unit 656 receives the title key from the firstportable medium insertion processing unit 655 sequentially acquires theencrypted content recorded on the first portable medium 4 via the firstportable medium access unit 62, sequentially descrambles the encryptedcontent using the title key, and sequentially outputs the result to theexterior via the output unit 63.

Though the above describes the construction of the user terminal 37 6 a,the other user terminals differ only in having TMIDb to TMIDn as userterminal identifiers and IKb to IKn as private keys. Descriptions of theother terminals are therefore omitted.

Operation

The following describes the operations of the clone terminal findingsystem 1, including, in order of appearance, (1) initial setting andupdate operations, (2) content purchasing operations, and (3) contentplayback operations.

The initial setting and update operations of (1) are the operationsperformed when a user is in possession of both the second portablemedium 5 a and the user terminal 6 a, and plays back the content byinserting former into the latter. The content purchasing operations of(2) are the operations performed when the user takes the second portablemedium 5 a to a retail outlet, purchases the first portable medium 4,and inserts the second portable medium into the information collectionserver 3 installed at the retail outlet. The content playback operationsof (3) are the operations performed when the user returns home with thepurchased first portable medium 4 and, in order to view the content,inserts the first portable medium 4 and the second portable medium 5into the user terminal 6 a.

(1) Initial Setting and Update Processing

The initial setting and update operations are described below withreference to FIG. 11.

Here, it is assumed that a user wishing to purchase the contents is inpossession of the user terminal 6 a and the second portable medium 5 a.The value TMIDa is assumed to be written as the user terminal identifierinto the storage unit 64 in the user terminal 6 a at shipping.Similarly, IKa is assumed to be written as the private key 672, andCRND1 a as the first user terminal random number 673. It is furtherassumed that user terminal table 501 is empty of data, as shown in FIG.3A.

First, the user inserts the second portable medium 5 a into the cardslot of the user terminal 6 a.

The second portable medium access unit 61 detects the insertion, andtransmits the insertion notification to the second portable mediuminsertion processing unit 651 (Step S601).

On receipt of the insertion notification, the second portable mediuminsertion processing unit 651 reads the user terminal identifier 671“TMIDa” from the storage unit 64 (Step S602).

The second portable medium insertion processing unit 651 then searchesthe data in the second portable medium via the second portable mediumaccess unit 651, and judges whether or not a user terminal identifier ofthe same value (i.e. TMIDa) is recorded (Step S603).

If a user terminal identifier having a value of TMIDa is not recorded onthe second portable medium 5 a (NO in Step S603), the second portablemedium insertion processing unit 651 outputs the user terminalidentifier TMIDa to the terminal information writing unit 652. Theterminal information writing unit 652 receives the user terminalidentifier TMIDa from the second portable medium insertion processingunit 651.

The terminal information writing unit 652 then reads the first userterminal random number 673 “TMRND1 a”, and records the user terminalidentifier 671 and the first user terminal random number 673 in the userterminal table in the second portable medium 5 a via the second portablemedium access unit 61, and ends the processing (Step S604).

At this stage, the user terminal table 501 recorded in the secondportable medium 5 a is in the state shown in FIG. 3B.

On the other hand, if a user terminal identifier having a value of TMIDais recorded on the second portable medium 5 a (YES in Step S603), thesecond portable medium insertion processing unit 651 judges whether ornot the second user terminal random number corresponding to the userterminal identifier “TMIDa” is recorded on the second portable medium 5a (Step S605), and if judging in the negative (NO in Step S605),proceeds to Step S607, which is described below.

If judging that the second user terminal random number corresponding tothe user terminal identifier “TMIDa” is recorded (YES in Step S605), theuser terminal table 501 recorded in the second portable medium 5 a is inthe state shown in FIG. 3C, and the second portable medium insertionprocessing unit 651 outputs the second user terminal random numberTMRND2 a to the terminal information update unit 654. Further, thesecond portable medium insertion processing unit 651 writes the value ofthe second user terminal random number over the first user terminalrandom number that is recorded in the second portable medium 5 a, anddeletes the second user terminal random number, via the second portablemedium access unit 61.

The terminal information update unit 654 receives the second userterminal random number TMRND2 a from the second portable mediuminsertion processing unit 651, and writes the value of the second userterminal random number TMRND2 a over the first user terminal randomnumber stored in the storage unit 64 (Step S606).

Next, the second portable medium insertion processing unit 651 judges,via the second portable medium access unit 61, whether or not a titleidentifier and encrypted title key corresponding to the user terminalidentifier TMIDa are recorded on the second portable medium (Step S607).If judging in the negative (NO in Step 607), the second portable mediuminsertion processing unit 651 ends the processing. If judging in theaffirmative (YES in Step 607), the second portable medium insertionprocessing unit 651 reads the title identifier and the encrypted titlekey, transmits the read title identifier and encrypted title key to theencrypted title key decryption unit 653, and deletes the titleidentifier and encrypted title key that correspond to the user terminalidentifier TMIDa from the second portable medium 5 a.

At this stage, the user terminal table 501 recorded on the secondportable medium 5 a is in the state indicated in FIG. 3D.

The encrypted title key decoding unit 653

The encrypted title key decryption unit 653 receives the titleidentifier and the encrypted title key from the second portable mediuminsertion processing unit 651, acquires the private key 672 from thestorage unit 64, and obtains the title key by decrypting the encryptedtitle key using the private key 672.

If, for example, the title key is “TLID1”, and the encrypted title keyis Enc(IKa, TLK1) (i.e. the title key “TLK1” encrypted using the privatekey “IKa”) the encrypted title key decrypting unit 653, receives TLID1and Enc (IKa, TLK1) from the second portable medium insertion processingunit 651, acquires the private key 672 “IKa” from the storage unit 64,and obtain the title key TLK1 by decrypting the encrypted title keyEnc(IKa, TLK1) using on the private key IKa.

The encrypted title key decryption unit 653 adds, as a piece titleinformation, the received title identifier in combination with obtainedtitle key to the title information table 681 stored in the storage unit64 (Step S608), and ends the processing.

(2) Contents Purchasing Processing

Here, it is assumed that the terminal information of the user terminal 6a, including the user terminal identifier TMIDa and the user terminalrandom number TMRND1 a, has been recorded on the second portable medium5 a by way of the above-described initial setting operations.

The user takes the second portable medium 5 a to a retail outlet,purchases the first portable medium 4, and inserts the second portablemedium 5 a in the card slot provided in the information collectionserver 3. The first portable medium has recorded thereon encryptedcontent ENCCNT1 (i.e. ENC(TLK1, CNT1)) identified by the titleidentifier TLID1.

The following describes the contents purchasing operations withreference to FIG. 8.

In the information server 3, the second portable medium access unit 32detects insertion of second portable medium 5 a has into the card slot,and transmits insertion notification to the second portable mediuminsertion processing unit (Step S301).

The second portable medium insertion processing unit 341, receives theinsertion notification, and acquires the user terminal identifier TMIDaand the first user terminal random number TMRND1 a (Step S302).

The second portable medium insertion processing unit 341 outputs theacquired user terminal identifier TMIDa and the first user terminalrandom number TMRND1 a to the transmission data generation unit 343(Step S303), and outputs a title information request to the titleinformation acquisition unit 342.

The title information acquisition unit 342 receives the titleinformation request from the second portable medium insertion processingunit 341, and transmits to the display 35 an instruction to display amessage prompting the user to input the title identifier. The displayunit 35 displays the message in accordance with the instruction.

Prompted by the message, the user inputs the title identifier TLID1,which identifies the purchased content, via the external input unit 33.

The title information acquisition unit 342 acquires the title identifierTLID1 from the external input unit 33 (Step S304), and outputs theacquired title identifier to the transmission data generation unit 343(Step S305).

The transmission data generation unit 343 acquires the user terminalidentifier TMIDa and the first user terminal random number TMRND1 a fromthe second portable medium insertion processing unit 341, receives thetitle identifier TLID1 from the title information acquisition unit 342,generates the transmission data including the user terminal identifierTMIDa, the first user terminal random number TMRND1 a, and the titleidentifier TLID1, and outputs the transmission data to the transmissionprocessing unit 344 (Step S306).

The transmission processing unit 344 receives the transmission data fromthe transmission data generation unit, and transmits the receivedtransmission data to the management server 2 via thetransmission/reception unit 31 (Step S307).

The management sever 2 receives the transmission data and performs clonejudgment processing using the transmission data (Step S308). The clonejudgment processing is described in a later section.

The management server 2 transmits terminal update data generated in theclone judgment processing to the information collection server 3.

The terminal update data includes the second user terminal random numberTMRND2 a, the title identifier TLID1, and the encrypted title keyENCTLK1 (i.e ENC(IKa, TLK1)).

The transmission/reception unit 31 in the information collection server3 awaits receipt of the terminal update data from the management server2 (NO in Step S309), and on receipt of the terminal update data (YES inStep S309), transmits the terminal update data to the receptionprocessing unit 345.

The reception processing unit 345 outputs the second user terminalrandom number TMRND2 a, the title identifier TLID1, and the encryptedtitle key ENCTLK1, which are contained in the received terminal updatedata, to the second portable medium data writing unit 346 (Step S310).

The second portable medium data writing unit 346 receives the seconduser terminal random number TMRND2 a, the title identifier TLID1, andthe encrypted title key ENCTLK1, and records the received second userterminal random number TMRND2 a, the title identifier TLID1 and theencrypted title key ENCTLK1 on the second portable medium via the secondportable medium access unit 32 (Step S311).

The clone judgment processing performed by the management server 2 inStep S308 is described below with reference to FIG. 6.

The transmission/reception unit 21 in the management server 2 receivesthe transmission data from the information collection server 3, andtransmits the transmission data to the reception processing unit 241.

The reception processing unit 241, receives the transmission data,outputs the included user terminal identifier TMIDa and the first userterminal random number TMRND1 a to the terminal information verifyingunit 242, and outputs the user terminal identifier TMIDa and the titleidentifier TLID1 to the title key encryption unit 244 (Step S201).

The terminal information verifying unit 242 receives the user terminalidentifier TMIDa and the first user terminal random number TMRND1 a fromthe reception processing unit 241 (Step S202), judges whether or not asecond management server random number is stored in correspondence withthe user terminal identifier TMIDa in the storage unit 23 (Step S203).If the second management server random number is not stored (NO in StepS203), the terminal information verifying unit 242, proceeds to StepS207, which is described below. If the second management server randomnumber is stored (YES in Step S203), the terminal information verifyingunit acquires the second management server random number CRND2 a fromthe storage unit 23 (Step S204).

The terminal information verifying unit 242 judges whether or not thevalue TMRND1 a of first user terminal random number matches the valueCRND2 a of the second management server random number (Step S205), andif judging in the negative (NO in Step S205), proceeds to Step S207,which is described below. If judging affirmatively (YES in Step S205),the terminal information verifying unit 242 writes the value CRND2 a ofthe second management server random number over the value CRND1 a of thefirst management server random number that corresponds with the userterminal identifier TMIDa, deletes the second management server randomnumber CRND2 a, and proceeds to Step S210 (Step S206).

If judging that the value of the first user terminal random numberTMRND1 a fails to match the value of the second management server randomnumber CRND2 a (NO in Step S205), the terminal information verifyingunit 242, acquires the first management server random number CRND1 a,which corresponds to the user terminal identifier TMIDa, from thestorage unit 23 (Step S207).

The terminal information verifying unit 242 compares the value of thefirst user terminal random number TMRND1 a with the value of the firstmanagement server random number CRND1 a (Step S208), and if judging thatthe two match (YES in step S208), proceeds to Step S210. If judging thatthe two fail to match (NO in Step S208, the terminal informationverifying unit 242 indicates that the user terminal corresponding to theuser terminal identifier TMIDa is a clone. The information verifyingunit 242 then causes the display unit to display a screen containing amessage such as “Clone discovered: user terminal identifier TMIDa” (StepS209), and proceeds to Step S210.

The terminal information verifying unit 242 outputs the user terminalidentifier TMIDa to the terminal information generation unit 243, andoutputs an encrypted title key generation request to the title keyencryption unit 244 (Step S210).

The terminal information generation unit 243 acquires the user terminalidentifier TMIDa from the terminal information verifying unit 242,generates a new random number, and stores the generated random number inthe storage unit 23 in correspondence with the user terminal identifierTMIDa as the value of the second management server random number CRND2a.

The terminal information generation unit 243 also outputs the randomnumber to the transmission data generation unit 245 as the second userterminal random number TMRND2 a (Step S211).

The title key encryption unit 244 receives the user terminal identifierTMIDa and the title identifier TLID1 from the reception processing unit241, receives the encrypted title key generation request from theterminal information verifying unit 242, and acquires from the storageunit 23 the private key IKa that corresponds to the user terminalidentifier TMIDa and the title key TLK1 that corresponds to the titleidentifier TLID1.

The title key encryption unit 244 then encrypts the title key TLK1 usingthe private key IKa to generate the encrypted title key ENCTLK1=Enc(TLK1, IKa), and outputs the title identifier TLDID1 and the encryptedtitle key ENCTLK1 to the transmission data generation unit 245 (StepS212).

The transmission data generation unit 245 receives the second userterminal random number TMRND2 a from the terminal information generationunit 243, and receives the title identifier TLID1 and the encryptedtitle key ENCTLK1 from the title key encryption unit 244.

The transmission data generation unit 245 generates terminal update dataincluding the received second user terminal random number TMRND2 a, thetitle identifier TLID1, and the encrypted title key ENCTLK1, andtransmits the terminal update data to the transmission processing unit246 (Step S213).

The transmission processing unit 246 receives the terminal update datafrom the transmission data generation unit 245, transmits the terminalupdate data to the information collection server 3 via thetransmission/reception unit 21, and ends the processing (Step S214).

(3) Playback Processing

Here, it is assumed that after purchasing the first portable medium 4 inthe retail outlet, the user returns home, and, to view the content,inserts the first portable medium 4 and the second portable medium 5 ainto the user terminal 6 a. On insertion of the second portable medium 5a, the user terminal 6 a performs the update processing of Steps S605 toS608 in FIG. 11.

The following describes the content. playback processing with referenceto FIG. 12.

When the first portable medium 4 is inserted into the disk slot providedin the user terminal 6 a, the first portable medium access unit 62detects the insertion, and transmits insertion notification to the firstportable medium insertion processing unit 655. The first portable mediuminsertion processing unit 655 receives the insertion notification (StepS651).

The first portable medium insertion processing unit 655 acquires thetitle identifier TLIDI, which is recorded on the first portable medium,via the first portable medium access unit 62 (Step S652).

The first portable medium insertion processing unit 655 judges whetheror not the title key TLK1 corresponding to the title identifier TLID1 isstored in the storage unit 64 (Step S653), and if judging negatively (NOin Step S653), ends the processing. If judging affirmatively (YES inStep S653), the first portable medium insertion processing unit 655reads, from the storage unit 64, the title key TLK1 corresponding to thetitle identifier TLID1, which has been read from the first portablemedium 4 (Step S654), and outputs the title key TLK1 to the descrambleprocessing unit 656 (Step S655).

The descramble processing unit 656 receives the title key TLK1 from thefirst portable medium insertion unit 655, and then sequentially acquiresthe encrypted content ENCCNT1 from the first recording medium via thefirst portable medium access unit 62. The descramble processing unit 656then sequentially descrambles the encrypted content using the title keyTLK1, and sequentially outputs the result to an external display via theoutput unit 63.

When the descrambling of the encrypted content ENCCT1 and the outputtingof the content is complete, the descramble processing unit 656 ends theprocessing (Step S656).

ADDITIONAL DESCRIPTION OF EFFECTS OF EMBODIMENT

This additional description of the effects of the present inventionconcerns the case where one of the user terminals (in this case 6 a) hasbeen analyzed and the terminal information, which includes the userterminal identifier TMIDa, the private key IKa, and the first userterminal random number TMRND1 a, has been found.

When the terminal information has been found in this way, there is apossibility that a large number of clone terminals (one denoted 6 y)will appear on the market.

The user terminal 6 a and the clone terminal 6 y hold the same terminalinformation, including the user terminal identifier TMIDa, the privatekey IKa, and the first user terminal random number TMRND1 a.

Here, it is assumed that the user of the user terminal 6 a (user a) andthe user of the clone terminal (user y) are different users, and thatthe user a and user y have differing second portable media 5 a and 5 y.

Firstly, consider the normal scenario in which the user of the userterminal 6 a goes to purchase a first portable medium 4 containingcontent.

In this case, the second portable medium 5 a held by the user a isinserted into the information collection server 3 installed at theretail outlet.

The management server 2 then writes the encrypted title key and a newrandom number to the second portable medium 5 a. The new random numberis the second user terminal random number for the user terminal havingthe user terminal identifier TMIDa.

The user a inserts the second portable medium 5 a into the user terminal6 a. The value of the first user terminal random number is then updatedto the value of the second user terminal random number recorded on theportable medium 5 a.

When the user purchases another set of content, the user inserts thesecond portable medium 5 a in the information collection server 3installed in the retail outlet in the same way as before.

A new random number is then set as the first random number on the secondportable medium 5 a.

On receipt of the new random number via the information collectionserver 3, the management server 2 recognizes that the first userterminal random number of the user terminal 6 a that corresponds to theuser terminal identifier TMIDa has been updated.

Suppose that the user then subsequently goes to the retail output topurchase content.

In this case, the user y inserts the second portable medium 5 y into theinformation server 3 as described above.

At this stage, the second portable medium 5 y held by the user y isstoring the user terminal identifier TMIDa and the value of the firstuser terminal random number from the time at which terminal informationwas found.

Thus, the management server 2 recognizes that some user terminal 6 x,which corresponding to the user terminal identifier TMIDa, is holding anold first user terminal random number.

The management server 2 is aware that the first user terminal randomnumber of the user terminal 6 a that corresponds to the user terminalidentifier TMIDa has been updated to a new random number.

Consequently, the management server 2 judges that at least two userterminals holding the same user terminal identifier TMIDa are inexistence.

The management server then displays a warning indicating that one ormore clones of the user terminal corresponding to the user terminalidentifier TMIDa are in existence.

Thus, the embodiment of the present invention is able to efficientlydiscover and detect clones of user terminals.

In the case that one of the user terminals (6 a for instance) has beenanalyzed and the terminal information relating to the user terminal 6 a(the user terminal identifier TMIDa, the private key IKa, and the firstuser terminal random number TMRND1 a) has been found, it is possible toimagine another form of clone terminal in which the user terminalidentifier TMIDa is altered to a fake value (in this case TMIDZ) withthe aim of avoiding detection. Such a clone terminal is denoted cloneterminal 6 z.

However, in the embodiment of the present. invention the managementserver 2 provides the title key for the purchased encrypted content asan encrypted title key which has been encrypted using a private keywhich corresponds to the received user terminal identifier.

Consequently, if the user terminal identifier TMIDz is passed to themanagement server 2, the clone terminal 6 z, which holds the private keyIKa, will be unable to decrypt the received encrypted title key.

Consequently, the clone terminal 6 z is unable to output the purchasedcontent.

Thus, to replace the found user terminal identifier with a fake valueand supply the fake value to the management server 2 is pointless. Theembodiment of the present invention therefore effectively preventsillegitimate use of content in the case that the found user identifieris replaced with a fake value.

Modifications

The above-described embodiment is an exemplary implementation of thepresent invention. However, the present invention is not limited to thisembodiment and may take any of a number of forms without departing fromthe scope of the present invention. The following modifications are alsoincluded in the present invention

(1) In the embodiment, every time the second portable medium is insertedinto the information collection server and the management server 2acquires information from the information collection server, themanagement server 2 generates a random number. The random number is thenrecorded on the second portable medium as the second user terminalrandom number, and the random number of the user terminal is updated.However, the present invention is not limited to this arrangement. Therandom number of the user terminal may instead be updated only once in apredetermined period (a month, for example). Alternatively, the randomnumber may only be updated upon receipt of request signal for randomnumber update from an external party. A further possibility is that therandom number is updated upon a predetermined number of purchases (ten,for example). These arrangements can be realized by ensuring that whenupdated of the random number is unnecessary the management server 2neither generates a new random number nor stores the second userterminal random number on the second portable medium.

In the management server 2, when it is judged that there is no match inStep S205 and, subsequently, that the value of the first user terminalrandom number TMRND1 a matches the value of the first management serverrandom number CRND1 a in Step S208, the user terminal in question isdetermined not to be a clone terminal. This arrangement is made in viewof the possibility that some time is required before the random numberin the terminal is updated.

To increase the strictness of the criteria for judging clone terminals,a user terminal may be judged to be clone terminal in the case where itis judged that there is no match in Step S205. In this case theprocessing proceeds directly to Step S209.

(2) In the embodiment, random numbers are used in the terminalinformation. However, it is acceptable to use a value other than arandom number, provided the management server 2 can recognize the valueand the value cannot be easily inferred by a third party not inpossession of the corresponding user terminal. For instance, the valuemay be a serial number that starts at 0 and increments by 1 upon eachupdate. Alternatively, information relating to the time at which themanagement server 2 received the data from the information collectionserver 3 may be used. Information relating to the time at which thesecond portable medium is inserted into the information collectionserver 3 may be used. A count of a number of insertions of the secondportable medium into the information collection server 3 may be used.Information relating to a playback history made up of content titles maybe used. Alternatively, the information may be hash values deriving froma playback history.

(3) In the embodiment, random numbers are used in the terminalinformation. However, it is acceptable to use any value that isautomatically updated by the user terminal, provided the value cannot beeasily inferred by a third party not in possession of the correspondinguser terminal. For instance, time information relating to the lastinsertion of the second portable medium into the user terminal may beused. A count of the number insertions of the second portable mediuminto the user terminal may be used. When the value is automaticallygenerated in this way, the management server 2 is no longer required toupdate the terminal information. As a result, it is possible to reducethe load on the management server 2.

(4) The embodiment relates to a case where each user holds a singlesecond portable medium, but the present invention is not limited to suchan arrangement. For instance, each user may hold two or more portablemedia. If each of second portable media holds the same user terminalidentifier, the management server will receive the same user terminalidentifier via a plurality of second portable media. With thisarrangement, the management server 2 may either write a second userterminal random number, which corresponds to the user terminalidentifier, to only one of the second portable media, or write a samesecond user terminal random number to the plurality of second portablemedia. Of the two options, the former has the disadvantage that the userterminal random number cannot be updated if the user loses the secondportable medium storing the second user terminal random number. Thelatter, in contrast, has the advantage that the user terminal randomnumber can be updated even if the user loses the second portable mediumstoring the second user terminal random number. To realize the latter, arandom number update completion flag may be added to the terminalinformation recorded on the second portable medium. The random numbercompletion update flag is written to the value of the second userterminal random number recorded on the second portable medium when theupdating of the value of the first user terminal random number of hasbeen completed in all the user terminals. The addition of such a flagenables the same random number, which corresponds to a single userterminal identifier, to be written to a plurality of second portablemedia. Even if the terminal information is provided to the managementserver 2 via a plurality of second portable media, the management server2 only recognizes that the random number update is complete if therandom number completion flag is recorded.

(5) In the embodiment, the second portable medium is an SD card or thelike, but the second portable medium is not limited to being an SD card.An IC card capable of computation may be used instead of the SD card. Inthis case, the second portable medium may be set up to verify the userterminal using encryption processing or the like before providing theterminal information and title key information. This enables a moresecure system to be constructed. The random number update completionflag of modification (4) may be added within the IC card. This preventsan unauthorized user from illicitly altering the random number updatecompletion flag in the second portable medium.

Though described as a DVD-ROM, the first portable medium 4 is notlimited to being a DVD-ROM, and may alternatively be a BD, a CD-R or anyother similar medium capable of storing content. Moreover, the secondportable medium is not limited to being an SD card, but may be anyportable medium that permits overwriting of data.

(6) In the embodiment, the management server 2 provides titleinformation in response to the acquisition of the terminal informationby way of the second portable medium, but the present invention is notlimited to this arrangement. For instance, the management server maysimply acquire the terminal information without providing anyinformation. Alternatively, the management server 2 may grant a licensethat is valid for a fixed period (one month, for instance) to the userterminal in exchange for acquiring the terminal information by way ofthe second portable medium, and prevent the user terminal from usingcontent if the license is not updated during the fixed period.

(7) In the embodiment, the target of the clone finding system is a userterminal that outputs content, but the present invention is not limitedto this. For instance, the target of the clone finding system may be thesecond portable medium (for instance an SD card). Thus, the target maybe a train pass, book of tickets, a train ticket, an IC card, a creditcard, a cash card, a debit card, electronic money, an electronic ticket,a electronic passport, an electronic tickets, an input output managementcard, a driver's license, a social security card, a mobile telephone, aPDA, an STB (Set top box), an electronic book, a computer, an IC tag,computer software, an online game license, or the like. In any case, thetargets of clone finding system are each made to store random number,and this enables the clone finding system to be applied to technologiesother than the user terminal that outputs content.

(8) In the embodiment, the AES private key encryption method is used,but the present invention is not limited to using this method. Forexample, a different private key encryption method (such as DES) or apublic key encryption method (such as RSA) may be used.

(9) In the embodiment, the management server 2 judges that the userterminal corresponding to a user terminal identifier is a clone uponreceipt of two differing first user terminal random numbers, eachcorresponding to the same user terminal identifier. However, the presentinvention is not limited to such. For example, the management server 2may judge that user terminal corresponding to a user terminal identifieris a clone upon receipt of a predetermined threshold count (three forinstance) of differing first user terminal random numbers correspondingto the same user terminal identifier. With this arrangement, it ispossible to reduce the rate of erroneous detection. Moreover, thisarrangement is applicable to systems in which a plurality of userterminals has a common user terminal identifier.

For instance, a plurality of user terminals of the same mode may have acommon user terminal identifier. In such a system, the predeterminednumber is set to be at least the number of user terminals having thesame user terminal identifier. With this arrangement, it is possible todetect clones, even in systems in which a plurality of user terminalshas a common user terminal identifier.

(10) The management server 2 and the information collection server 3 inthe description are each provided with a modem or the like, andcommunicate using the modem, but the present invention is not limited tosuch an arrangement. For instance, the transmission/reception unit 21 ofthe management server 2 and the transmission/reception unit 31 of theinformation collection server 3 may be LAN adaptors, and thecommunication channel 7 may be the internet.

(11) In the embodiment, an example is described in which the thirteensecond portable media 5 a to 5 m are used, but the number of media isnot limited to thirteen. Twelve or fewer portable media may be used.Alternatively, fourteen or more portable media may be used. Although inthe example the fourteen user terminals 6 a to 6 n are used, the numberof user terminals is not limited to being fourteen. Fifteen or more userterminals may be used. Alternatively, thirteen or fewer user terminalsmay be used. Further, more than one information collection server 3 maybe used. Similarly, more than one type of title identifier and title keymay be used.

When the management server 2 is installed in the retail outlet, aread/write apparatus for accessing SD cards, which are used as thesecond portable media, may be used rather than the informationcollection server 3. In this case, the management server 2 may acquirethe title identifier by user input rather than the informationcollection server 3.

(12) In the embodiment, content is sold by the retail outlet, but thepresent invention is not limited to this arrangement, and may be appliedin cases where the content is rented or leased.

(13) The functional blocks of the control unit 24 of the managementserver 2, the control unit 34 of the information collection server, andthe control unit 65 of the each of the user terminals 6 a to 6 n, may bean integrated circuit using LSI. Each of these functional blocks may berealized as a single chip or be included as part of a single chip.

Though LSI is mentioned, the nomenclature varies with the degree ofintegration. Other names include IC, system LSI, super LSI, and ultraLSI.

A dedicated circuit or general-purpose processor may be used instead ofLSI methods to realize the integrated circuit. A FPGA (FieldProgrammable Gate Array, which programmable after LSI manufacturing maybe used. Alternatively, are configurable processor, which permitspost-manufacture alteration to. the connections and settings of thecells in the LSI, may be used.

Moreover, if anew technology that is an advanced or derivative form ofsemiconductor technology should replace LSI as a technology for formingintegrated circuits, the functional blocks may be integrated using thenew technology.

(14) The present invention may be any of the methods shown above.Alternatively, the present invention may be computer programs thatrealize these methods using a computer, or digital signals composed ofthe programs. The present invention may be a computer-readable recordingmedium having the computer program or digital signals recorded thereon,examples of which included flexible disk, hard disk, CD-ROM, MO, DVD,DVD-ROM, DVD-RAM, BD (Blu-ray Disc), and semiconductor memory etc.Alternatively, the present invention may be the computer programs ordigital signals recorded on any of these recording media. The presentinvention may be the computer programs or digital signals transmittedvia a data broadcast or a network the like, typical examples of whichinclude a telecommunications network, a wireless or cable network, andthe Internet. The present invention may be a computer system providedwith a microprocessor and memory, in which the memory stores thecomputer program and the microprocessor operates in accordance with thecomputer programs. The computer programs or digital signals may beexecuted on a separate independent computer system by transferring thecomputer program or digital signals recorded on the recording medium, orby transferring the computer programs or digital signals via a networkor the like.

(15) The present invention may be any combination of the aboveembodiments and modifications.

INDUSTRIAL APPLICABILITY

The unauthorized apparatus detection device, content playback device,information collection device, program, recording medium, and integratedcircuit of the present invention can be used in management systems forcontent that requires copyright protection, and can be manufactured andsold by industries that deal with computers and digital electronicdevices such as content playback devices and management servers for suchplayback devices.

1. An unauthorized apparatus detection device for detecting anunauthorized apparatus produced by copying, comprising: a distributionunit operable to store a first verification value in correspondence witha verification apparatus identifier, generate a second verificationvalue that differs from the first verification value, store the secondverification value in place of the first verification value, anddistribute the second verification value to an apparatus that is storingthe verification apparatus identifier; an acquiring unit operable toacquire from a portable medium a target apparatus identifier and averification value that have been written to the portable medium by adetection target apparatus; a judging unit operable, if the targetapparatus identifier matches the verification apparatus identifier, tojudge whether or not the acquired verification value matches the secondverification value; and a registering unit operable, if the judging unitjudges negatively, to register the target apparatus identifier on anunauthorized apparatus list.
 2. The unauthorized apparatus detectiondevice of claim 1, wherein if the judging unit judges affirmatively, thedistribution unit is further operable to generate a third verificationvalue that differs from the second verification value, store the thirdverification value in place of the second verification value, anddistribute the third verification value to the detection targetapparatus.
 3. The unauthorized apparatus detection device of claim 1,further comprising: a title key storage unit operable to store a titlekey for decrypting encrypted content, wherein if the judging unit judgesaffirmatively, the distribution unit further distributes the title keyto the detection target apparatus.
 4. The unauthorized apparatusdetection device of claim 2, the detection target apparatus storingtherein a private key, the unauthorized apparatus detection devicefurther comprising: a title key storage unit operable to store a titlekey for decrypting encoded content; a duplicate key storage unitoperable to store, in correspondence with the verification apparatusidentifier, a duplicate key that is a copy of the private key; and anencrypted title key generation unit operable to encrypt the title keyusing the duplicate key to generate an encrypted title key, wherein ifthe judging unit judges affirmatively, the distribution unit furtherdistributes the encrypted title key to the detection target apparatus.5. The unauthorized apparatus detection device of claim 1, furthercomprising: a counting unit operable to count a number of affirmativejudgments by the judging unit; and a count judging unit operable tojudge whether the total number of affirmative judgments exceeds apredetermined number, wherein if the total number exceeds thepredetermined number, the distribution unit is further operable togenerate a third verification value that differs from the secondverification value, replace the first verification value with the thirdverification value, and distribute the second verification value to thedetection target apparatus.
 6. The unauthorized apparatus detectiondevice of claim 1, further comprising: a period measuring unit operableto measure a period since a last verification value distribution by thedistribution unit; and a period judging unit operable to judge whetherthe total period exceeds a predetermined period, wherein if the totalperiod exceeds the predetermined period, the distribution unit isfurther operable to generate a third verification value that differsfrom the second verification value, replace the second verificationvalue with the third verification value, and distribute the thirdverification value to the detection target apparatus.
 7. Theunauthorized apparatus detection device of claim 1, wherein thedistribution unit is operable to generate a random number to use as eachverification value.
 8. A content playback device for performing playbackof content, comprising: a storage unit operable to store, incorrespondence with an apparatus identifier, a first verification valuegenerated by an unauthorized apparatus detection device for detecting anunauthorized apparatus produced by copying; a notification unit operableto notify the unauthorized apparatus detection device of the apparatusidentifier and first verification value; an acquiring unit operable toacquire from a portable medium an apparatus identifier and a secondverification value that have been written, in response to thenotification, on the portable medium by the unauthorized apparatusdetection device, the second verification value having been generated bythe unauthorized apparatus detection device; and an update unitoperable, if the acquired apparatus identifier matches the apparatusidentifier stored in the storage unit, to replace the first verificationvalue with the second verification value.
 9. An unauthorized apparatusdetection system for detecting an unauthorized apparatus produced bycopying, including an unauthorized apparatus detection device and aplurality of detection target apparatuses, each detection targetapparatus comprising: a storage unit operable to store a firstverification value in correspondence with a target apparatus identifier;a notification unit operable to notify the unauthorized apparatusdetection device of the target apparatus identifier and the firstverification value; an update information acquiring unit operable toacquire, from the unauthorized apparatus detection device, averification apparatus identifier and a second verification value thatis generated by the unauthorized apparatus detection device; and anupdate unit operable, if the verification apparatus identifier matchesthe target apparatus identifier, to replace the first verification valuewith the second verification value, and the unauthorized apparatusdetection device comprising: a distribution unit operable to generate asecond verification value that differs from a first verification valuestored in correspondence with a verification apparatus identifier, storethe second verification value in correspondence with the verificationapparatus identifier in place of the first verification value, anddistribute the verification apparatus identifier and the secondverification value to an apparatus that is storing the verificationapparatus identifier; an acquiring unit operable to acquire a targetapparatus identifier and a verification value from any one of thedetection target apparatuses; a judging unit operable, if the receivedtarget apparatus identifier matches the verification apparatusidentifier, to judge whether or not the acquired verification valuematches the second verification value, and a registering unit operable,if the judging unit judges negatively, to register the target apparatusidentifier on an unauthorized apparatus list.
 10. The unauthorizedapparatus detection system of claim 9, wherein the notification unit isfurther operable to write the target apparatus identifier and the firstverification value to a portable medium, and the acquiring unit isfurther operable to read the target apparatus identifier and theverification value from the portable medium via an informationcollecting device.
 11. The unauthorized apparatus detection system ofclaim 10, wherein the information collecting device includes: a readingunit operable to read from the portable medium the target apparatusidentifier and the verification value that are written in the portablemedium; and a transmission unit operable to transmit the targetapparatus identifier and the verification value, and the acquiring unitacquires the target apparatus identifier and the verification value fromthe information collecting device.
 12. An information collecting devicefor transmitting, to an unauthorized apparatus detection device fordetecting unauthorized apparatus produced by copying, information storedby a detection target apparatus that is a target of the detection, thedetection target apparatus storing a target apparatus identifier and averification value generated by the unauthorized apparatus detectiondevice, and the unauthorized apparatus detection device generating theverification value, storing the generated verification value incorrespondence with a verification apparatus identifier, acquiring atarget apparatus identifier and a verification value, if the targetapparatus identifier matches the verification apparatus identifier,judging whether the stored verification value matches the acquiredverification value, and if judging negatively, registering the targetapparatus identifier on an unauthorized-apparatus list, the informationcollecting device comprising: a reading unit operable to read from theportable medium the target apparatus identifier and the verificationvalue that have been written to the portable medium by the detectiontarget apparatus; and a transmission unit operable to transmit the readtarget apparatus identifier and the read verification value to theunauthorized apparatus detection device.
 13. An unauthorized apparatusdetection method for detecting an unauthorized apparatus produced bycopying, comprising: a distribution step of storing a first verificationvalue in correspondence with a verification apparatus identifier,generating a second verification value that differs from the firstverification value, storing the second verification value in place ofthe first verification value, and distributing the second verificationvalue to an apparatus that is storing the verification apparatusidentifier; an acquiring step of acquiring from a portable medium atarget apparatus identifier and a verification value that have beenwritten to the portable medium by a detection target apparatus; ajudging step of, if the target apparatus identifier matches theverification apparatus identifier, judging whether or not the acquiredverification value matches the second verification value; and aregistering step of, if the judging unit judges negatively, registeringthe target apparatus identifier on an unauthorized apparatus list.
 14. Acomputer program used in a storage unit-equipped unauthorized apparatusdetection unit for detecting an unauthorized apparatus produced bycopying, comprising: a distribution step of storing a first verificationvalue in correspondence with a verification apparatus identifier,generating a second verification value that differs from the firstverification value, storing the second verification value in place ofthe first verification value, and distributing the second verificationvalue to an apparatus that is storing the verification apparatusidentifier; an acquiring step of acquiring from a portable medium atarget apparatus identifier and a verification value that have beenwritten to the portable medium by a detection target apparatus; ajudging step of, if the target apparatus identifier matches theverification apparatus identifier, judging whether or not the acquiredverification value matches the second verification value; and aregistering step of, if the judging unit judges negatively, registeringthe target apparatus identifier on an unauthorized apparatus list. 15.The computer program of claim 14, wherein the computer program isrecorded on a computer-readable recording medium.
 16. An apparatusinformation update method used by a content playback device forperforming playback of content, the content playback device including astorage unit operable to store, in correspondence with an apparatusidentifier, a first verification value generated by an unauthorizedapparatus detection device for detecting an unauthorized apparatusproduced by copying; and the apparatus information update methodcomprising: a notification step of notifying the unauthorized apparatusdetection device of the apparatus identifier and first verificationvalue; an acquiring step of acquiring from a portable medium anapparatus identifier and a second verification value that have beenwritten, in response to the notification, on the portable medium by theunauthorized apparatus detection device, the second verification valuehaving been generated by the unauthorized apparatus detection device;and an update step of, if the acquired apparatus identifier matches theapparatus identifier stored in the storage unit, replacing the firstverification value with the second verification value.
 17. A computerprogram used by a content playback device for performing playback ofcontent, the content playback device including a storage unit operableto store, in correspondence with an apparatus identifier, a firstverification value generated by an unauthorized apparatus detectiondevice for detecting an unauthorized apparatus produced by copying; andthe computer program comprising: a notification step of notifying theunauthorized apparatus detection device of the apparatus identifier andfirst verification value; an acquiring step of acquiring from a portablemedium an apparatus identifier and a second verification value that havebeen written, in response to the notification, on the portable medium bythe unauthorized apparatus detection device, the second verificationvalue having been generated by the unauthorized apparatus detectiondevice; and an update step of, if the acquired apparatus identifiermatches the apparatus identifier stored in the storage unit, replacingthe first verification value with the second verification value.
 18. Thecomputer program of claim 17, wherein the computer program is recordedon a computer-readable recording medium.
 19. An integrated circuit usedcontent playback device for performing playback of content, comprising:a storage unit operable to store, in correspondence with an apparatusidentifier, a first verification value generated by an unauthorizedapparatus detection device for detecting an unauthorized apparatusproduced by copying; a notification unit operable to notify theunauthorized apparatus detection device of the apparatus identifier andfirst verification value; an acquiring unit operable to acquire from aportable medium an apparatus identifier and a second verification valuethat have been written, in response to the notification, on the portablemedium by the unauthorized apparatus detection device, the secondverification value having been generated by the unauthorized apparatusdetection device; and an update unit operable, if the acquired apparatusidentifier matches the apparatus identifier stored in the storage unit,to replace the first verification value with the second verificationvalue.